I've got a doorknob in need of replacement. However, the old doorknob's faceplate is riveted to a larger plate (see picture). Is the larger plate a standard part that I can buy somewhere, or is it a custom job? (Does the larger plate have a name?) I can probably drill out the rivets, but I figure that's plan B.

Someone's idea of a security upgrade? I guess it would support the latch better (screws into more solid wood that's not got the lock bores out of it) in the face of a "kick down the door" attack. You might be able to replace the knob and re-use the latch - many are the same internal workings.
– EcnerwalMar 10 '15 at 2:05

Should I post a picture of the internals to see if you (or someone else) recognizes it? FWIW, It doesn't have a square shaft through the middle like some other doorknobs I've seen. It has a hollow half-cylinder go through the middle instead. The knob is made by Kwikset.
– lnmaurerMar 10 '15 at 3:01

Then another Kwikset would probably be compatible - you might be able to tell from looking at directions for specific sets you are considering - on the other hand, should not be too hard to just swap the plate to the next latch as Jack describes.
– EcnerwalMar 10 '15 at 3:13

2 Answers
2

Go with plan B. The larger strike looks like either of two things, a reinforcement for a damaged mount for the strike bolt. The door slab looks ever so slightly thicker at the strike location, like the screws somehow split the door at the strike. Or the door originally had a mortise lock set and this part serves as an adapter so to get a standard knob to work in the large cut out for a mortise lock.

I really think it is the former, not the latter. Either way you need to at least reuse it, or replace it if you can find one at the big box stores. I have seen them before. It should be where all the replacement parts for old style doors are located, I do not know what it is called. You can remove it temporarily if it helps you drill out the pop rivets. Also, it may help the store guy see what you need if you want a new one anyway just to freshen up the look to go with the new knob.
You can drill out the pop rivets which MAY be 3/16" but drill first with a 1/8" bit, and if it doesn't fall apart, then use the 3/16". After that you can purchase a standard bore latch set and new pop rivets and get it all back together again.

For what its worth, you could do away with reassembling it with pop rivets and go with 8 gauge flathead machine screws in a bright brass finish to match everything, and use "stop nuts" to hold it together. Get a couple of screws to replace the drywall screws to balance it all out.

If you feel adventurous and you have worked with chisels before and you are adept at it, you could add a "Dutchman" of substantial depth to do away with the secondary metal plate, and get it closer to the way it is meant to be

For what appears to be an apartment door that might have been kicked in, (one way for the screws to split the wood, anyway) I'd keep the metal rather than rebuilding it in wood...
– EcnerwalMar 10 '15 at 3:14

Keeping the metal would truly be the simplest way. It can be done with wood, but that is geared more for an experienced wood worker. I have done it before, it takes great care, clamps, wood blocks for the clamps to keep the door flat and hold in the glued in parts, oh yeah, lots of glue.
– JackMar 10 '15 at 5:15

That would be a great question to ask at the new Woodworking.se that's just about to launch. Go ask about a dutchman there!
– FreeManMar 10 '15 at 17:53

That door originally had a mortise lock and I'm assuming this is in an old building. It looks like someone custom made an adapter plate to put a modern bored cylindrical lock in as a replacement.

You can either find a replacement mortise lock (just do a google search and you will find lots of sites that have replacement hardware). Or you can go with your plan B and drill out the rivets.

But a warning if you go with plan B. Without the original mortise lock in the door cavity, the door will be very weak without it. If that adapter plate is only covering the hole, and not filling the hole, one kick will completely break the door there.

For what it's worth, an 1 3/8" thick door, one kick is all it takes for a standard bore door. Think about how much wood is actually left when the 2 1/8" drilled hole goes in and then cross bored with a 7/8" or 1" diameter hole from the edge that is only an 1 3/8" thick. That leaves only 1/4" of wood at best on either side of the latch bolt that is only held in place by 3/4" long screws. Not much better than a mortise door latch. If somebody wants to get in, they will get in.
– JackMar 10 '15 at 5:20